Analysis and Design of a 12-Element Coupled-Microstrip-Line quasi-TEM Resonator for MRI

Using the finite element method (FEM) and method of moments (MoM) in two dimensions, the electromagnetic (EM) analysis and design of a n-element coupled-microstrip-line quasi-TEM resonator are presented. The analysis allows the determination of the primary inductive and capacitive matrices ([L], [C]) and simulates the frequency response of S11 at the RF port of the designed n-element inhomogeneous MRI probe. As an application, we present the design results of a MRI probe loaded with a biological element of dielectric constant of εr = 57.50 and using a 12-element coupled-microstrip-line quasi-TEM resonator. The probe with high Q operates at 340 MHz (proton imaging at 8 T) and has -90 dB minimum reflection. The MRI probe using twelve-element coupled-microstrip-line is easy to construct, inexpensive, and simple to operate. Furthermore, the coil presented here may be constructed to work at different resonances frequencies.